I'm standing in the wings of the Menier Chocolate Factory theatre in London with playwrights Enda Walsh and Dennis Kelly. We're all trouser-wetting nervous. We have agreed to take part in an evening called Speak, in which playwrights perform their own work. The audience anticipation is growing, an announcement is made, we hug each other - and we're on.

February 26

The next day. A lie in. It was a good night. The audience seemed to enjoy the pieces. An idea begins to form in my head. I phone the other playwrights: would they like to take these pieces further and perform some more? I get a very firm "no" from both of them.

March 3

I've been thinking about my piece: a monologue for a film executive to a starlet, pitching a film about her love for a suicide bomber. I'm sure it could be developed further, and I'd like to see if I can carry on performing it. I tentatively broach this with Lucy Morrison, who directed the original evening. Relief. She doesn't laugh. She thinks it's a good idea.

March 20

We've got the backing of Roxana Silbert, artistic director of Paines Plough. Why don't we perform it in a late-night slot at the Traverse during the Edinburgh festival? I decide not to tell her that the last time I acted in the Fringe, as a student nearly 20 years ago, I set fire - accidentally - to the venue. She sends in the script.

April 4

This is terrible. However many things you've written, waiting for people to read your script and get back to you is horrible.

April 25

We're programmed: 9.45pm in Traverse 2 for the second two weeks of the festival. That's terrible, too, in a different way. Now there is no going back.

June 20

Lucy and I have begun a two-week workshop at the National Theatre Studio. We want to find the shape of the script over this fortnight, so that after that I can concentrate solely on being an "actor". Lucy is very strict about this: at any one time, she will talk to either "writer" or "actor", never both at the same time. It's the only way, she says, to ensure I concentrate.

June 22

My head's bursting. We've been reading essays and articles about terrorism and Islam for nearly two days now.

June 24

Siobhan Stamp comes in to do voice work with me. I'm going to be doing 45 minutes of non-stop talking every night for two weeks, and I want my voice to hold up. We spend a day doing hums and pants and whoops until my whole body is buzzing. It feels great to speak when even the small of your back is resonating.

June 27

I've been working on a new draft of the text. Lucy and I felt by the end of last week that we needed to find out more about who my character is. But as I read the latest version to Lucy, I realise I don't like it. Lucy works on it with me. I still don't like it. I feel depressed. A week's workshop and I've come up with a draft that's a step back from the previous one.

June 28

I wake up at 4.30am worrying about the script. I'm too inexperienced an actor to be landed with a duff script. After an hour, I get out of bed and start writing another draft.

June 29

Wake up at 5am. Write. I tell Lucy I'm not happy with the "character-based" draft. She agrees that it was a step back. I tell her I'll have a fresh approach tomorrow.

June 30

Up at 5.30am. Write. We read it through. It works. Relief. It's getting close to what I set out to write.

July 1

We read through the script for a few people connected with the production. It seems to go well. Lucy tells me that, apart from cutting the odd line or doing a small rewrite, I should regard the script as finished and concentrate on the acting. That will be a much bigger challenge for me.

July 4

We start working on the text in a Stanislavski-ish way, breaking it down into "units of action" and then giving each line a transitive verb, something you're trying to do to the other, silent character - to seduce, to bully, to educate. This is going to take most of this week.

July 6

I try a section of the text, playing the "actions". They're more useful than I could ever have imagined. They make acting concrete, focused - and pleasurable. A lot of the stress seems to leave my body as I do my bit. Yes!

July 7

I learn about the London bombs in a phone call from the playwright April de Angelis, just as I'm about to set off for rehearsals. I phone Lucy. We agree not to rehearse that day. What does our play mean now, with its story of a London suicide bombing? Its meaning has no doubt changed, but we're not sure how.

July 8

We look through the script. Should we be rewriting it? Should most of the black humour be removed on grounds of taste? Or should we be updating it to make it even more topical? In the end, we decide to leave the script as it is. I think both of us have a sense that events in the real world are likely to carry on changing around the play.

July 15

I sit down and start to learn the play. This is a big hurdle. What if I can't learn lines? It's a petty but very practical consideration in the middle of all the shock and grief on the television.

July 16

The script is going in pretty easily. This is a big relief.

July 21

Lucy and I are walking into the West End from rehearsals in Camden. Warren Street station is surrounded by police, helicopters, TV crews. We stand, our way blocked, overwhelmed by the spectacle of the event. Is our play any kind of response to this? When I wrote it, fundamentalist terrorist attacks seemed like a possibility. Now they're here. Can my monologue articulate anything about them? I'll only know when I'm in front of an audience in Edinburgh.

August 4

First run-through. Shaky in places. But I got there. And sometimes I was actually right inside the thing, inhabiting it. Which I guess is how an actor feels. It's a good feeling.

August 11

Here I go again. We're doing a couple of invited preview performances before we head off to Edinburgh. I'm sitting in a small cupboard that passes for a dressing room and I can hear the theatre filling up. I feel very sick. Is it a good thing or a bad thing to run through the words in my head now? Probably a bad thing. I turn off the light and curl up in a ball in the corner. The stage manager comes in to cue me - and almost misses me. "Why are you down there in the dark? You're on." Ahhhh!

· Product is at the Traverse, Edinburgh, until August 28. Box office: 0131-228 1404.